The broad, long-term objective of the proposed project is to ensure safety, quality, and accessibility of anesthesia care. The specific aims are to characterize hospital-level factors associated with anesthesia-related complications (ARC) during labor and vaginal deliveries (L&VD), quantify their costs, and analyze their temporal trends. Utilization of anesthesia care during L&VD has increased 50% during the last decade. Although more than 2 million anesthesia procedures are annually performed in increasingly comorbid women, safety of anesthesia care during L&VD has not been adequately studied. ARC occur in one out of every 200 parturients and are more frequent in women with preexisting conditions. Previous research suggests that some hospital-level factors are associated with an increased risk of adverse safety events and may account for the marked between-hospital variation observed in adverse outcomes. They may include independent nurse anesthetist practice, low-delivery volume, rural location, or teaching status. Characterization of hospital-level factors associated with ARC and accounting for their between-hospital variation may help identify areas for further safety investigation or intervention to improve maternal outcomes. Furthermore, ARC lead to significant costs with a median of $220,000 per liability claim. They are twice the liability costs of other anesthesia specialties but are uninformative for practice and policy changes. Hospital costs associated with ARC can be estimated from hospital charges. Costs of ARC will provide information on their financial burden and on the potential to reduce this burden through safety investigation and interventions. They also provide a ranking for intervention using their cost-based criticality, the product of the incidence and cost-based severity of ARC. Finally, recent research indicates a decrease in ARC during cesarean delivery during the last decade but no study has specifically examined L&VD. Analysis of temporal trends in the incidence and costs associated with ARC during L&VD will indicate whether obstetric anesthesia safety is improving and may identify groups of hospitals with an abnormal increase in ARC indicating a safety concern. Analysis of complications and costs in women clustered within hospitals requires advanced statistical techniques taking into consideration correlation of women within hospitals, such as multilevel modeling. In the proposed project, we will use multilevel modeling to characterize hospital-level risk factors for ARC and their between hospital variation during L&VD in the 2013-2014 State Inpatient Database for New York State, a census of inpatient discharge abstracts in community hospitals. We will also analyze costs associated with ARC and the temporal trends in the incidence and costs associated with ARC using the National Inpatient Sample from 2003 to 2014, a national representative sample of approximately 20% of discharges records from community hospitals.